81166801 has 4 divisors (see below), whose sum is σ = 81524592. Its totient is φ = 80809012.

The previous prime is 81166769. The next prime is 81166807. The reversal of 81166801 is 10866118.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81166801 - 2⁵ = 81166769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81166807) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 178555 + ... + 179008.

It is an arithmetic number, because the mean of its divisors is an integer number (20381148).

Almost surely, 2^81166801 is an apocalyptic number.

It is an amenable number.

81166801 is a deficient number, since it is larger than the sum of its proper divisors (357791).

81166801 is a wasteful number, since it uses less digits than its factorization.

81166801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 357790.

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 81166801 is about 9009.2619564535. The cubic root of 81166801 is about 432.9716658171.

The spelling of 81166801 in words is "eighty-one million, one hundred sixty-six thousand, eight hundred one".